I wanted the interior to look mostly stock, but with a few updates. I wanted to add a few gauges and put in 3 point safety belts. I wanted to get the air conditioning and radio working, but leave them looking basically stock. And I wanted to freshen up the interior with new upholstery and carpet.
The original steering wheel that came from the factory was 17" diameter. When I bought the truck, the steering wheel had already been changed to a 15" GM "comfort grip" wheel with a blue outer rim (on my red/green truck), and a Buick logo on the horn button. So I replaced that with a new comfort grip wheel, but with a black outer rim and a Chevy bowtie logo on the horn button. As a bonus, I got the horn to work with the parts that came with the steering wheel. The comfort grip wheel was available on Chevelles, Camaros and Corvettes.
The gas pedal was replaced with one from Lokar. This changes the original rod & pivot throttle linkage to a cable linkage. The cable throttle linkage makes it easier to put the throttle and transmission kickdown linkage on the carb.
The original seat belts were only lap belts, but Chevy put anchor points into the rear upper cab to mount shoulder belts. I installed a lap/shoulder belt kit from Brothers Trucks.
I reused the existing seat frame, but got new seat covers in off white vinyl with black/white houndstooth cloth inserts and new seat foam from Classic Parts - they are actually made by PUI Interiors. I'm happy with the seat back foam, although I really did not need it. On the seat bottom, I really did not need new foam either - I'm actually not happy with the new seat bottom foam - it made the seat fabric so tight that I needed to use zip ties instead of hog rings in a few spots to get an extra inch here and there. And the new seat bottom makes the seat so high that it is hard to get my legs past the steering wheel and my head almost touches the roof. I'm saving the old seat bottom foam and may take apart the seat and put the old foam back. But I am happy with the new vinyl/fabric cover.
I installed a grey dash pad & parchment armrests from Classic Parts.
I put in black nylon loop carpet from Auto Custom Carpets, This is available from several vendors, and I used Early Classic.
I liked the look of the original dash, but I wanted to make some changes. The original dash only had a speedometer and fuel gauge. There was an option that added an ammeter, water temperature, and oil pressure gauges - this came standard on the "CST" trim level. The optional gauge panel still left a large hole in the middle of the panel. I wanted a voltmeter instead of an ammeter, and I wanted to add an Air/Fuel ratio gauge. So I decided to fit aftermarket gauges that followed the factory layout.
I got a new factory dash bezel, and put a panel over it from Front Panel Express with cutouts for the gauges and indicator lights. Since the dash has an irregular outside shape, I started with a CAD file for the outline - Draw1A.dxf. I then took that outline and used software from Front Panel Express to make cutouts for the dash items - DashSpeedHutB.fpd. I found indicator lights for the turn signals and high beam lights intended for a Ford Cobra. I got gauges from SpeedHut. The speedometer and tachometer are 4" diameter, and the speedometer is a GPS unit. The GPS antenna is small and sits under the dash near a plastic defrost vent to get a good signal. The other gauges are 2 5/8" diameter with a 90 degree sweep, come with very good sending units, and have built in warning lights that can be programmed to come on when the readings are too low or high.
The original radio was an AM radio, but it did not work when I bought the truck. This was replaced with a Model One radio from Retrosound. The radio looks like an old radio with knobs, but it has a USB connector for music files, or it can connect with a 1/8" inch jack to an MP3 player or smartphone. The Retrosound Model One is an older model and is not made by Retrosound any more, but there are similar newer models that include a Bluetooth connection.
The factory speaker was a single (mono) 4 x 10 speaker that is in a frame called a "special rectangle". I wanted a single 4 x 10 speaker with dual speaker drivers to get stereo. There are 4 x 10 speakers that have a single woofer and dual tweeters in them, but the A/C vent just below the speaker does not generally allow room for the speaker magnet. A better way to go is to get a 4 x 10 speaker with two 3.5" or 4" speakers. I'm using a single unit with 2 drivers from Electro-Tech that fits in the original 4 x 10 "special rectangle" size speaker location in the top front of the dash. This is the "Stereo High Output" version with dual 4" speakers.
The Air Conditioning system was replaced with a Vintage Air system. Since my truck originally had factory AC, this system uses the original in-dash control, but puts a new faceplate on it to indicate the correct functions. This system has electric switches & motors only - no cables or vacuum are used to open/close dampers. The Vintage Air system uses the original dash vents. The heater - A/C unit fits higher up under the dash than stock, and you lose depth in the glove compartment. The under hood housing goes away, since it has been moved behind the dash.
To get the old parts off of the firewall, the passenger-side inner fender needs to be removed to get access to the screws holding the heater/AC box to the firewall. The inner fender is removed by removing 7 screws along the outside of the fender - these are held on with "J-nuts", which are a captive screw on a metal clip. These tend to rust - I had to grind 2 screw heads off since the J-nuts allowed the screw to turn without unscrewing it. The inner fender is also held on with a large screw in the middle-back, 2 screws near the top that go into the fender, and 1 that goes into the battery box. After that, there are 3 screws at the bottom front. After the inner fender is loose, you can access the 4 nuts holding the AC evaporator and 2 screws holding the fan on. Make sure the heater hoses are completely removed, and the unit on the firewall should then be able to be pulled off.
Now under the dash, the glove box door is removed with the 4 screws along the bottom hinge edge, and 2 screws holding the door limiter on. Then there are several screws along the perimeter of the cardboard glove box - once these are removed, the box pushes into the dash and can be pulled out from underneath. At this point there is an enclosure on the inside of the firewall that houses the heater core - this comes off with 2 screws at the 5 and 11 o'clock positions from the inside of the firewall.
There are several heater/AC vent boxes under the dash - remove these carefully, along with the flexible ducts. On my truck, the ducts were still functional, but any pulling on them made them disintegrate. There will be cables on some of the boxes that need to be removed. The only things that are being reused are the control panel, the 2 defrost vents, the 2 round vents at each end of the dash, and the rectangular vent above the radio.
One of the slider arms on my dash control was broken off, so I got a replacement dash control assembly from Vintage Air.
Here are a few lessons learned after installing the Vintage Air heater/AC: